Project Info

Lived morphologies and body development of Cambrian arthropods and nemathelminths, a testtool for phylogeny analyses and hypotheses

There are four major sources of exquisitely preserved early representatives of various metazoan taxa: Lower Cambrian Chengjiang or Maotianshan-Shale lagerstaetten in China, a Lower Cambrian lagerstaette on Greenland at the Sirius Passet, Middle Cambrian lagerstaetten of the Burgess-Shale type worldwide and Lower to Lower Ordovician "Orsten" lagerstaetten, also worldwide. Fossils from these Lagerstaetten have contributed significantly to our knowledge of early metazoan evolution and the morphologies and life styles developed at the time, when metazoan life began to radiate. Many questions have become satisfactorily resolved, but major questions remained, such as: Where do the arthropods belong to systematically? Which is the closest relative? In 1997, the long-standing dogma of a sister-group relationship with annelids was questioned and the idea of a nemathelminth-arthropod relationship put forward. Still today, this is not resolved. Focusing on representatives of arthropods and nemathelminths from the fossil lagerstaetten mentioned above, we want to investigate, in a comparative-morphological approach, original material. Priority is given to structural and functional aspects of body design and development. This includes critical aspects of the evolution of segments and tagmata including appendage formation, features most likely primary absent in nemathelminths. Our particular aim is to present the data accumulated from these "lived morphologies" as a testtool for phylogeny hypotheses resulting from other work groups within the Priority Programme.